Valve, especially for hydraulic automotive brake systems

Abstract

The present invention relates to a valve, especially for slip-controlled brake systems in automotive vehicles, with a valve tappet guided in a valve housing and including a valve closure member, with a valve seat facing the valve closure member, and with a piezoelectric element for actuating the valve closure member. A first and a second force transmission element is arranged between the piezoelectric element and the valve tappet, wherein the first force transmission element is made of a high-strength material that elastically deforms the second force transmission element in the direction of the valve tappet when the piezoelectric element is activated electrically.

1. A valve comprising:
 a valve tappet guided in a valve housing and including a valve closure member; 
 a valve seat facing the valve closure member; and 
 a piezoelectric element for actuating the valve closure member, 
 wherein a first and a second force transmission element is interposed between the piezoelectric element and the valve tappet, 
 wherein the first force transmission element is made of a high-strength material which elastically deforms the second force transmission element in the direction of the valve tappet when the piezoelectric element is activated electrically, and 
 wherein for sensing the hydraulic pressure by way of the two force transmission elements, the pressure applied to the valve closure member acts on the piezoelectric element, and the electric change in voltage of the piezoelectric element resulting from mechanical deformation is converted into a pressure value by means of an electronic evaluating unit. 
 
   
   
     2. The valve as claimed in  claim 1 , wherein for the mechanic translation of the piezoelectric movement onto the valve tappet, a contact surface of the second force transmission element that abuts on the end surface of the valve tappet is smaller than a contact surface of the second force transmission element that abuts on the first force transmission element. 
   
   
     3. The valve as claimed in  claim 1 , wherein the second force transmission element seals the hydraulically applied inside area of the valve housing in relation to the dry inside area of the valve housing. 
   
   
     4. The valve as claimed in  claim 1 , wherein the second force transmission element is composed of an elastomer or a silicone. 
   
   
     5. The valve as claimed in  claim 1 , wherein the second force transmission element is preloaded by choosing the adjustment depth of the piezoelectric element in the valve housing. 
   
   
     6. The valve as claimed in  claim 1 , wherein the piezoelectric element is supported with its end surface remote from the first force transmission element on a cover that closes the valve housing and is displaceable for adjusting the piezoelectric element in the valve housing. 
   
   
     7. Valve as claimed in  claim 1 , wherein the piezoelectric element is configured as a piezo block in a stack-type construction, and in that the first force transmission element is configured as a piston that is guided along the inside wall of the valve housing and bears against the second force transmission element designed as a cushion. 
   
   
     8. The valve as claimed in  claim 1 , wherein the second force transmission element is composed of a silicone cushion. 
   
   
     9. Valve as claimed in  claim 1 , wherein the piezoelectric element is arranged between the first force transmission element and an elastically preloaded compensating piston, whose position is influenced by the physical properties of an elastic mass fixed in the valve housing. 
   
   
     10. Valve as claimed in  claim 9 , wherein the physical properties of the elastic mass correspond to the physical properties of the second force transmission element which is elastically compressed between the first force transmission element and the bottom of the valve housing. 
   
   
     11. Valve as claimed in  claim 9 , wherein the elastic mass is embedded as a compensating ring into an annular compensating bowl that is supported on a bottom of a housing step of the valve housing. 
   
   
     12. Valve as claimed in  claim 9 , wherein the compensating piston is designed as an annular piston which points with its open end portion into a compensating bowl and is pressed there onto a elastic mass by the action of an elastic preloading force. 
   
   
     13. Valve as claimed in  claim 12 , wherein a cup spring assembly produces the preloading force active on the compensating piston, with the cup spring assembly being compressed between the closed bottom of the compensating piston and a closure plug arranged at the end of the sleeve-shaped valve housing. 
   
   
     14. Valve as claimed in  claim 9 , wherein the first force transmission element is designed as a piston having its piston skirt guided in the opening of a annular compensating bowl, and in that the first force transmission element plunges into the opening of the valve housing wherein a elastically deformable second force transmission element is inserted in a fluid-impermeable fashion. 
   
   
     15. Valve as claimed in  claim 9 , wherein the elastic mass is composed of a rubber reaction disc and the second force transmission element is composed of a rubber ring. 
   
   
     16. Valve as claimed in  claim 9 , wherein the valve housing comprises two first and second housing sleeves that are jointed in sections into one another at their ends, with the housing sleeve including a piezoelectric element being grouped with the two force transmission elements, a compensating ring, a compensating bowl, the compensating piston, and a closure plug to form an independent assembly. 
   
   
     17. Valve as claimed in  claim 16 , wherein a compression spring and a valve tappet are mounted between the two housing sleeves, with the valve tappet at the portion remote from a valve seat in the valve housing being guided in a sleeve projection at the first housing sleeve. 
   
   
     18. Valve as claimed in  claim 9 , wherein for the purpose of mechanical transmission of the piezoelectric movement onto the valve tappet, the contact surface of the second force transmission element that abuts on the end surface of the valve tappet is smaller than the contact surface of the second force transmission element, said contact surface abutting on the first force transmission element. 
   
   
     19. The valve as claimed in  claim 2 , wherein the second force transmission element seals the hydraulically applied inside area of the valve housing in relation to the dry inside area of the valve housing. 
   
   
     20. A valve comprising:
 a valve tappet guided in a valve housing and including a valve closure member; 
 a valve seat facing the valve closure member; 
 a piezoelectric element for actuating the valve closure member; 
 a first force transmission element interposed between the piezoelectric element and the valve tappet and abutting the piezoelectric element; 
 a second force transmission element interposed between the piezoelectric element and the valve tappet and abutting the valve tappet, wherein the first force transmission element is made of a high-strength material which elastically deforms the second force transmission element in the direction of the valve tappet when the piezoelectric element is activated electrically; and 
 an electronic evaluating unit responsive to the piezoelectric element, 
 wherein the electronic evaluating unit measures the electric change in voltage of the piezoelectric element and converts it into a pressure value for sensing the hydraulic pressure applied to the valve closure member.